kwin/plugins/platforms/x11/common/ge_event_mem_mover.h
2020-08-07 19:57:56 +00:00

44 lines
1.2 KiB
C++

/*
KWin - the KDE window manager
This file is part of the KDE project.
SPDX-FileCopyrightText: 2018 Martin Flöser <mgraesslin@kde.org>
SPDX-License-Identifier: GPL-2.0-or-later
*/
#pragma once
#include <xcb/xcb.h>
#include <cstring>
namespace KWin
{
class GeEventMemMover
{
public:
GeEventMemMover(xcb_generic_event_t *event)
: m_event(reinterpret_cast<xcb_ge_generic_event_t *>(event))
{
// xcb event structs contain stuff that wasn't on the wire, the full_sequence field
// adds an extra 4 bytes and generic events cookie data is on the wire right after the standard 32 bytes.
// Move this data back to have the same layout in memory as it was on the wire
// and allow casting, overwriting the full_sequence field.
memmove((char*) m_event + 32, (char*) m_event + 36, m_event->length * 4);
}
~GeEventMemMover()
{
// move memory layout back, so that Qt can do the same without breaking
memmove((char*) m_event + 36, (char *) m_event + 32, m_event->length * 4);
}
xcb_ge_generic_event_t *operator->() const {
return m_event;
}
private:
xcb_ge_generic_event_t *m_event;
};
}